Microwave radio frequency (RF) transmission systems typically are point-to-point, and thus often utilize waveguide channels to focus, or restrict, the direction of propagation of the electromagnetic (EM) signaling to a desired direction. Coplanar waveguides (CPWs) often well suited to integrated microwave or other RF applications due to their relatively high field confinement that reduces interference with other signal traces and unwanted couplings. Conventional implementations facilitate the transition from a CPW to a waveguide channel by inserting a launcher element (also often called a probe element) into a monolithically-formed waveguide channel through an aperture in a transverse wall of the monolithic waveguide channel near the closed end of the monolithic waveguide channel, which then acts to either to focus EM signaling emitted by the feedline or to focus received EM signaling to the feedline. Impedance matching is achieved by shorting a back wall of the waveguide channel proximate to the launcher element within a quarter-wavelength of the EM signaling of the back wall. In some conventional approaches, this spacing is achieved by partially filling the back of the monolithic waveguide channel with dielectric material and then inserting the launcher element. However, errors in the fabrication of the CPW and launcher element or misalignment when inserting the launcher element into the monolithic waveguide can result in erroneous positioning of the launcher element relative to the back wall, and thus can degrade the performance of the CPW-to-waveguide-channel transition. The impact of such fabrication and assembly errors is particularly manifest in systems intended for communicating millimeter-wave (mmW) frequencies of 30 gigahertz (GHz) and higher due to the relatively tight design tolerances for such systems.